New research may help
connect the dots between traumatic brain injury and the risk for memory and
other brain-related problems later in life.

Brain imaging technology
known as positron emission tomography (PET) shows that people who have had a
traumatic brain injury develop so-called "plaques" in their brain
like those seen in the brains of people with Alzheimer's disease, the most
common type of dementia.

"Our research has
shown, for the first time, that PET imaging can show amyloid deposits in the
brain after head injury," said study author Dr David Menon of the anaesthesia
division at the University of Cambridge, England. And these deposits can show
up within hours of the blow to the head.

Cognitive decline

Previous studies have
linked a history of head injury with higher odds of developing memory problems
later in life, but it is too early to say that the head injury is the cause.

"Patients can be
imaged with PET to detect early amyloid deposition, and then followed up to see
whether this early amyloid deposition resolves, whether it recurs, and how
these processes relate to later cognitive [mental] decline," Menon said.

For this study, researchers
used PET imaging to look at the brains of 15 people with traumatic brain injury
and 11 healthy individuals with no history of brain trauma. The images were
taken between one day and close to a year after the head injury.

The researchers also
examined brain tissue samples taken from people who died after head injury and
those who died of non-brain-related causes. The findings are published in the online
edition of JAMA Neurology.

The greater the blow to the
head, the more amyloid plaque accumulation and dementia risk was seen, Menon
said. Individuals most at risk may include those who also have a genetic
predisposition to Alzheimer's disease, he said.

In recent years, former
professional athletes who sustained head injuries and went on to develop such
memory and mood problems have received a lot of media attention. But this study
did not include athletes, just people with injuries severe enough to warrant
admission to an intensive care unit. On average, they were in their 30s.

Immediate damage

Other experts not involved
with the study stress the significance of these findings.

"The study shows
evidence of these plaques days after the accident," said Dr Mony de Leon,
director of the Centre for Brain Health at NYU Langone Medical Centre in New
York City. "It is not like someone got hit on the head at age 32 and can't
remember anything at age 60. The damage is immediate, and now we have a way of
seeing it."

He pointed out that amyloid
plaques are a hallmark of Alzheimer's disease in the brain, but they are not
the only marker. Tangled or twisted strands of another protein are also seen in
the brains of people with Alzheimer's disease. "This study is highly
suggestive that there is an Alzheimer's disease-like effect in the brain after
head injury, but it's not definitive because we can't see the tangles,"
said de Leon.

Still, the potential
at-risk group is huge, he said. It includes athletes, soldiers and individuals
hurt in car crashes.

The study, while small, is
important, said Dr Robert Glatter, an emergency physician at Lenox Hill
Hospital in New York City and a former sideline physician with the NY Jets.

Objective biomarkers

"This type of imaging
may potentially play a role in helping to understand how traumatic brain injury
affects the brain and serve as a marker to evaluate such patients over the long
term," he said. If treatments are developed, this type of imaging will
help determine whether or not they work.

Dr Sam Gandy, director of
the Mount Sinai Centre for Cognitive Health in New York City, cautioned that
the imaging research is still in the early stage.

"There is currently great interest in
identifying objective biomarkers [or indicators] to document the structural and
functional [consequences] of chronic and mild traumatic brain injury,"
Gandy said.

But PET scans have been
used far less often in diagnosing sports-related brain damage than brain harm
caused by traffic accidents, he noted.

More information

The US Centres for Disease
Control and Prevention has more about the risks associated with traumatic brain
injury.

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